A variety of media content streaming techniques are employed to deliver media content to client devices. Virtual Reality (VR) content is intended to provide an immersive experience in which a user is apparently surrounded by and interacts with a virtual environment constructed from actual or computer-generated images. The original source images from which VR content is constructed correspond to different views from the user's apparent location at the center of the environment (e.g., front, back, left, right, etc.). In order to encode the source images, the images are combined to form a two-dimensional (2D) representation (e.g., an equirectangular projection of a polygonal projection) in which each of the combined images corresponds to a portion of a three-dimensional (3D) shape, for instance, a cylinder or a cube. Typically, the 2D representation includes non-display pixels that do not contain image content. When non-display pixels are included during the encoding process, playback of the VR content can include visual artifacts, which disrupt a user's viewing experience.